(1) Field of the Invention
The present invention relates to a thermoplastic crosslinked rubber composition. More particularly, the present invention relates to a thermoplastic crosslinked rubber composition with superior appearance, feeling, heat and light stabilities, scratch resistance, oil resistance and mechanical strength
(2) Description of the Related Art
A thermoplastic elastomer composition obtained by, so to speak, dynamic crosslinking, that is crosslinking during melt mixing of a radically crosslinkable elastomer and a radically non-crosslinkable resin such as polypropylene (PP) in an extruder in the presence of a radical initiator, is well known technology and widely used in applications such as automotive parts.
As one of such rubbery compositions, a composition prepared by applying the dynamic crosslinking technology to an olefinic elastomer is known (JP-A-8-120127 and JP-A-9-137001). However, it has not necessarily been satisfied in the market due to its inferior scratch resistance.
One the other hand, as examples of dynamic crosslinking technology using a rubber other than olefinic elastomers, the followings are known: A dynamically crosslinked elastomer composition comprising an olefinic elastomer together with a hydrogenated diene rubber, compounded further with a crystalline α-olefinic polymer, an ethylenic polymer and a softening agent (JP-A-9-302156), and a thermoplastic elastomer composition obtained by melt mixing of a polyolefinic resin and a random or a block copolymer of a conjugated diene type monomer and an aromatic vinyl monomer in the presence of a crosslinking agent (JP-A-3-2240). None of these compositions has enough mechanical strength, scratch resistance, appearance and heat and light stabilities. Thus there remains a need of a thermoplastic rubber composition acceptable for the practical use.